Up until recently the exchange cases started with 44xxxxx.It is believed that those numbers have been used and later re-case numbers begin with 47xxxxx.Sie besteht aus einer zufallsgenerierten Kombination aus Zahlen und Buchstaben.Dies hat zur Folge, dass von nun an nur noch Rolex das Produktionsjahr der Uhren kennt.
There are a few web sites out there that are about Wrist Watches, some about Pocket Watches too, but I've struggled to come across many that have enough information in the one place to be of much use.
Rolex Oyster Case Listings 1926 – 2003 Rolex watches are dated by a serial number which corresponds to the actual manufacture date.
The date of market introduction may vary however, so expect to add 6 to 18 months.
This chart is compiled from several lists to give you an approximation of the earliest numbers seen for certain years.
Use it to bracket the number you are looking up to give you a best approximation of the production date for that example.